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Quantifying the Climate Impacts of Albedo Changes Due to Biofuel Production: a Comparison with Biogeochemical Effects Quantifying the climate impacts of albedo changes due to biofuel production: a comparison with biogeochemical effects The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Caiazzo, Fabio, Robert Malina, Mark D Staples, Philip J Wolfe, Steve H L Yim, and Steven R H Barrett. “Quantifying the Climate Impacts of Albedo Changes Due to Biofuel Production: a Comparison with Biogeochemical Effects.” Environmental Research Letters 9, no. 2 (January 1, 2014): 024015. As Published http://dx.doi.org/10.1088/1748-9326/9/2/024015 Publisher Institute of Physics Publishing Version Final published version Citable link http://hdl.handle.net/1721.1/86306 Terms of Use Creative Commons Attribution Detailed Terms http://creativecommons.org/licenses/by/3.0/ Home Search Collections Journals About Contact us My IOPscience Quantifying the climate impacts of albedo changes due to biofuel production: a comparison with biogeochemical effects This content has been downloaded from IOPscience. Please scroll down to see the full text. 2014 Environ. Res. Lett. 9 024015 (http://iopscience.iop.org/1748-9326/9/2/024015) View the table of contents for this issue, or go to the journal homepage for more Download details: IP Address: 18.51.1.88 This content was downloaded on 03/04/2014 at 15:31 Please note that terms and conditions apply. Environmental Research Letters Environ. Res. Lett. 9 (2014) 024015 (10pp) doi:10.1088/1748-9326/9/2/024015 Quantifying the climate impacts of albedo changes due to biofuel production: a comparison with biogeochemical effects Fabio Caiazzo, Robert Malina, Mark D Staples, Philip J Wolfe, Steve H L Yim and Steven R H Barrett Laboratory for Aviation and the Environment, Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA, USA E-mail: [email protected] Received 17 October 2013, revised 16 January 2014 Accepted for publication 17 January 2014 Published 26 February 2014 Abstract Lifecycle analysis is a tool widely used to evaluate the climate impact of greenhouse gas emissions attributable to the production and use of biofuels. In this paper we employ an augmented lifecycle framework that includes climate impacts from changes in surface albedo due to land use change. We consider eleven land-use change scenarios for the cultivation of biomass for middle distillate fuel production, and compare our results to previous estimates of lifecycle greenhouse gas emissions for the same set of land-use change scenarios in terms of CO2e per unit of fuel energy. We find that two of the land-use change scenarios considered demonstrate a warming effect due to changes in surface albedo, compared to conventional fuel, the largest of which is for replacement of desert land with salicornia cultivation. This corresponds to 222 gCO2e=MJ, equivalent to 3890% and 247% of the lifecycle GHG emissions of fuels derived from salicornia and crude oil, respectively. Nine of the land-use change scenarios considered demonstrate a cooling effect, the largest of which is for the replacement of tropical rainforests with soybean cultivation. This corresponds to −161 gCO2e=MJ, or −28% and −178% of the lifecycle greenhouse gas emissions of fuels derived from soybean and crude oil, respectively. These results indicate that changes in surface albedo have the potential to dominate the climate impact of biofuels, and we conclude that accounting for changes in surface albedo is necessary for a complete assessment of the aggregate climate impacts of biofuel production and use. Keywords: albedo, biofuels, climate, lifecycle S Online supplementary data available from stacks.iop.org/ERL/9/024015/mmedia 1. Introduction US EPA 2013). In the US, biofuel production for transportation aims to replace 30% of petroleum consumption by 2030 Biofuels may hold promise to promote energy security, re- (Perlack et al 2005, US Department of Energy 2011). Targets duce the environmental impact of transportation and foster are also set for the EU (10% replacement of diesel and gasoline economic development. For these reasons, many countries by 2020; EU 2009) and other countries such as China (2 million have enacted policies to encourage their production (EU 2009, tons of biodiesel by 2020; Koizumi 2011) and Indonesia (20% replacement of diesel and gasoline by 2025; Zhou and Content from this work may be used under the terms of Thomson 2009). the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the Historically, environmental assessments of biofuels have title of the work, journal citation and DOI. focused on biogeochemical effects (i.e. greenhouse gas (GHG) 1748-9326/14/024015C10$33.00 1 c 2014 IOP Publishing Ltd Printed in the UK Environ. Res. Lett. 9 (2014) 024015 F Caiazzo et al emissions) directly or indirectly attributable to the lifecycle quantify and compare the albedo effect of replacing an original of the fuel. Emissions are considered for all relevant life- land use with the cultivation of palm, rapeseed or salicornia, cycle steps, including feedstock cultivation, extraction, and in particular. The LUC scenarios considered are derived from transportation as well as fuel production, distribution, and Stratton et al (2010, 2011a) and the albedo effects are presented combustion (Kim and Dale 2005, Larson 2006, Lardon et al in terms of gCO2e/MJ of renewable middle distillate (MD) 2009, Yee et al 2009, Stratton et al 2010, Van der Voet fuel, which is the fuel considered in the Stratton et al (2011a) et al 2010, Guinee´ et al 2011). Land-use change (LUC) to lifecycle analysis. This enables a consistent comparison of cultivate biomass feedstock for biofuel production may lead the LUC-induced albedo effect, the biogeochemical effects to GHG emissions if it changes the amount of carbon stored from LUC, and the GHG emissions from the production of in vegetation and soil (Stratton et al 2010). renewable MD fuels. Distinct from assessing the biogeochemical effects, there is limited research focused on the biogeophysical effects 2. Methodology of LUC for biomass feedstock cultivation. Biogeophysical effects include changes in surface albedo (Betts 2000, Lee In this study, we evaluate the induced albedo effect of a number et al 2011), evapotranspiration (Pitman et al 2009, Georgescu of discrete LUC scenarios. Each of these scenarios is evaluated et al 2011), surface roughness/canopy resistance (Lean and at multiple geographic locations in order to account for Rowntree 1993, Betts 2007, Georgescu et al 2009), leaf area variability in surface and meteorological conditions within the index and rooting depth of the vegetation (Georgescu et al same land types involved in the LUC. Satellite measurements 2009). Of these, the LUC-induced change in surface albedo of albedo and transmittance parameters are retrieved for each geographic location of interest, and an analytical radiative is considered the dominant biogeophysical effect at the global balance model is used to convert the albedo changes into a scale (Betts 2000, 2001, Claussen et al 2001, Bala et al 2007). RF, then into equivalent GHG emissions. A change in albedo alters the surface reflectivity of sunlight (the incoming shortwave radiation), thus changing the Earth’s radiative balance. Albedo changes can be quantified in terms 2.1. LUC scenarios of global radiative forcing (RF) (Betts 2000, Georgescu et al We consider eleven LUC scenarios, comprised of five different 2011, Bright et al 2012, Cherubini et al 2012), which can be biomass feedstocks for up to three original land uses each, as expressed in terms of GHG equivalent emissions (Betts 2001, shown in table1. Each scenario is restricted to one geographic Bird et al 2008). This allows for a direct comparison against region. The scenarios are consistent between this study and the the biogeochemical effects calculated by traditional LCA. traditional LCA study that we use as a reference (Stratton et al In contrast, additional biogeophysical effects such as 2010; LUC combinations S1, S2, P1, P2, P3, H1), wherever evapotranspiration and surface roughness cannot be ade- possible. The switchgrass and rapeseed scenarios are redefined quately expressed in terms of global RF (Davin et al 2007, due to ambiguities in the reference LCA study. In Stratton et al Betts 2011, Cherubini et al 2012), although they may be (2010), switchgrass cultivation is assumed to take place on relevant at a local scale (Bounoua et al 2002, Georgescu et al generic carbon-depleted soils. In this study we consider three 2011). In previous work, the climate impact of albedo changes possible LUC scenarios associated with carbon-depleted soils has been assessed to describe the effect of forestation policies (McLaughlin et al 2002, Adler et al 2007): corn cultivation (Rautiainen et al 2009, Lohila et al 2010, Rautiainen et al (LUC B1), soybean cultivation (LUC B2), and barren land 2011). Recent studies have also attempted to evaluate the (LUC B3) replaced by switchgrass cultivation. Furthermore, in albedo effect of biomass feedstock cultivation, using either the reference LCA rapeseed cultivation in Europe is assumed numerical models (Georgescu et al 2011, Anderson-Teixeira to take place on set-aside land, i.e. land areas temporarily et al 2012, Hallgren et al 2013, Anderson et al 2013) or satellite removed from agricultural production (Stratton et al 2010). In measurements (Bright et al 2011, Loarie et al 2011, Cherubini this case we consider
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